In conventional vehicle windshields, a plurality of curved glass sheets are adhered together via a plastic film such as polyvinyl butyral. Before being adhered, the glass sheets are often heated, bent and/or stacked in an adjacent or overlapping manner. In order to easily separate the sheets and/or to prevent sheets from fusing together during bending, diatomaceous earth powder and/or oxy powder is often sprinkled on or between the sheets. Before the polyvinyl butyral adhesion layer is inserted between the glass sheets, cleaning should be performed in order to remove the powder(s) from the sheet surfaces.
FIG. 1 is a side elevation view of a prior art glass washing (or cleaning) apparatus 3. The apparatus includes a frame having a plurality of upright support columns 5 connected to horizontal members 7, and a continuous conveyor adapted to support glass sheets 21 in a generally horizontal plane for movement from loading station 9, to wetting station 11, to scrubbing station 13, to rinsing station 15, to drying station 17, and finally to unloading station 19. Wetting station 11 includes a plurality of fixed nozzles 25 for discharging streams of cleansing liquid against the upper and lower surfaces of glass sheets 21. At scrubbing station 13, cleaning brushes 27 rotatingly contact sheets 21 in order to remove dirt therefrom. Sheets 21 are then rinsed at station 15 by a plurality of fixed spray nozzles 29, and thereafter are blown dry at station 17 by blowers 31. Additional details of the FIG. 1 apparatus may be found in U.S. Pat. No. 4,352,221, the disclosure of which is hereby incorporated herein by reference.
Unfortunately, it is undesirable to utilize cleaning brushes which contact the glass sheets. Because of the many different sized and shaped glass sheets that may be fed through such an apparatus, it would be time consuming, expensive and burdensome to be often changing brushes as a function of the sheets to be cleaned (different sized and/or shaped brushes may be needed for different shaped sheets). It is also undesirable to keep an inventory of many different brush types, most of which are not even used at the same time. Moreover, brushes may scratch the glass should dirt or other particles become lodged therein. Additionally, powder to be cleaned from the sheet may coagulate on brushes, resulting in frequent brush maintenance.
Another disadvantage associated with the apparatus of FIG. 1 is that it transports glass sheets through the various stations in a horizontal orientation. Conveyor rolls may be positioned between the glass surface to be cleaned and spray nozzles. This can prevent or inhibit liquid from the nozzles from impacting different points on is the glass.
It is apparent from the above that there exists a need in the art for an apparatus for cleaning (or washing) curved glass sheets, and a corresponding method, which solves one or more of the aforesaid problems and/or results in one or more of the following advantages: (i) elimination of contacting brushes; (ii) an improved system for cleaning glass sheets; (iii) a more efficient system for cleaning glass sheets; (iv) an improved system/method of drying glass sheets; and/or (v) a system which can transport single sheets of glass through a cleaning apparatus in a substantially upright manner.
It is a purpose of this invention to fulfill any or all of the above-identified needs in the art, as well as other needs which will become apparent to the skilled artisan from the following detailed description of this invention.